mast cell

A cell found in connective tissue that contains numerous basophilic granules and releases substances such as heparin and histamine in response to injury or inflammation of bodily tissues.

[Partial translation of German Mastzelle, well-fed cell (from an early view that the granules were from phagocytosis) : Mast, food, mast (from Middle High German, from Old High German) + Zelle, cell.]

A connective tissue cell whose specific physiologic function remains unknown; capable of elaborating basophilic, metachromatic, cytoplasmic granules that contain histamine.

Large cells, often capable of amoeboid movement, found in connective and fatty tissue. They release substances such as leukotrienes histamine and heparin during allergic reactions and the inflammation response.

A cell that may be derived from an undifferentiated precursor, which may be of monocytic origin, in the perivascular connective tissue. It elaborates granules that contain histamine, heparin and, in the rat and mouse, serotonin. It plays an important role in acute hypersensitivity (type I) reactions such as atopy and anaphylaxis.

• m. c. leukemia — see mast cell leukemia.
• m. c. tumor — a benign, local aggregation of mast cells forming a nodular tumor that occurs in the skin of most species, but most commonly in dogs. The release of histamine or other vasoactive substances may be associated with gastroduodenal ulceration. These tumors may become malignant. See also mastocytosis.